NiCu alloy nanoparticles encapsulated in nitrogen-doped carbon nanotubes for highly efficient acidic hydrogen evolution reaction

The use of low-cost non-precious metals to replace platinum as electrocatalysts for the hydrogen evolution reaction (HER) holds great potential, but their efficiency and stability still face challenges. Here, we report a nitrogen-doped carbon nanotube (NCNT) supported NiCu-x (x = 0.5, 1, 2) electrocatalyst for the hydrogen evolution reaction (HER) under acidic conditions. By optimizing the atomic molar ratio of Ni/Cu alloy nanoparticles, the optimal NiCu-1 catalyst was obtained, featuring a thin carbon shell and uniformly distributed alloy nanoparticles, and exhibiting outstanding HER activity. The NiCu-1 catalyst requires only 42 mV overpotential to achieve a current density of 10 mA/cm 2 . Its high electrochemical active surface area and low electron transfer resistance contribute to enhanced HER catalytic performance. Furthermore, the 40 h current density stability test demonstrates excellent durability of the catalyst. DFT calculations indicate that the optimized bimetallic composition and structure significantly enhance the electron transfer rate. The approach proposed in this work provides a new strategy for developing efficient, stable, and cost-effective materials for sustainable energy conversion systems. • NiCu-1 catalyst achieves 42 mV overpotential at 10 mA/cm 2 , rivaling Pt/C in acidic HER. • Excellent stability over 40 h demonstrates durability for long-term applications. • DFT reveals enhanced electron transfer via optimized NiCu alloy and N-doped carbon support. • Cost-effective, non-precious metal catalyst advances sustainable hydrogen energy systems.